System and method for removing particulate matter from a diesel particulate filter

ABSTRACT

A system is provided for removing particulate matter from a particulate filter. The system includes an engine controller coupled to a sensor and an engine, and a locomotive controller coupled to the engine controller. The sensor outputs a first alert signal to the engine controller, including the current load and the loading rate of one or more particulate filter units. The engine controller determines a projected load and projected loading rate of the one or more particulate filter units along a route, and a time gap or distance gap based on a trip plan until the one or more particulate filter units are fully loaded. The engine controller determines a time region or distance region to remove particulate matter from the filter unit.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 11/838,296, filed on Aug. 14, 2007, now U.S. Pat.No. 7,925,431. This application is further related to U.S. patentapplication Ser. Nos. 11/838,277 and 11/838,299, filed concurrently withone another on Aug. 14, 2007. Each of the foregoing applications isincorporated by reference herein in their entirety.

FIELD OF THE INVENTION

This invention relates to aftertreatment systems, such as a dieselparticulate filter, and more particularly to a system and method forremoving particulate matter from a diesel particulate filter.

BACKGROUND OF THE INVENTION

Diesel engines have been extensively used in various applications, suchas locomotives, for example. Diesel engine exhaust gas is typicallyoutputted from the engine (or a turbocharger connected to the dieselengine) and directed to an output, such as to the atmosphere for alocomotive diesel engine, for example.

More stringent emissions standards on diesel engines have led to theintroduction of aftertreatment systems to reduce emissions. Particulatematter is one such emissions constituent that is being more aggressivelyregulated. Strict particulate standards have led to the use ofparticulate trapping devices in the exhaust systems. These devices actlike a filter to capture particulate matter in the exhaust.

After a prolonged period of operating time, the diesel particulatefilter of the conventional system will become backlogged with excessivetrapped particulate matter. This trapped particulate matter may beremoved from the diesel particulate filter using various techniques,such as regeneration, for example. Regeneration is a technique used toclean particulate filters onboard the locomotive, when the particulatefilter has captured enough soot particles to restrict exhaust flow belowan acceptable level. Regeneration is accomplished by increasing thetemperature of the particulate filter, causing the soot particles tooxidize and burn off of the particulate filter. The regeneration processtypically removes carbon particles from the particulate filter, leavingonly a small amount of ash. The accumulated ash eventually needs to beremoved, but this removal process is usually undertaken during ascheduled maintenance. However, none of the conventional systemsefficiently remove the trapped particulate matter from the dieselparticulate filter, thus leading to a poor diesel exhaust gas flow rateand inefficient diesel engine operation.

Accordingly, it would be advantageous to provide a system to efficientlyremove the trapped particulate matter from the diesel particulatefilter, to improve the efficiency of the diesel engine while minimizingthe energy loss resulting from such removal.

BRIEF DESCRIPTION OF THE INVENTION

One embodiment of the present invention provides a system for removingparticulate matter from a diesel particulate filter. The dieselparticulate filter includes at least one diesel particulate filter unitto filter the particulate matter from diesel engine exhaust gas receivedfrom a diesel engine of a locomotive. Additionally, the system includesan engine controller coupled to the diesel engine. Furthermore, thesystem includes a locomotive controller coupled to the enginecontroller. Additionally, the locomotive controller includes analgorithm to create a trip plan to optimize the performance of thelocomotive along a route in accordance with a power setting of thediesel engine at each location along the route. Each sensor isconfigured to output a first alert signal to the engine controller uponthe trapped particulate matter exceeding a predetermined threshold. Theengine controller is configured to communicate with the locomotivecontroller upon receiving the first alert signal to determine a timeregion or distance region within the trip plan when the power settingexceeds a power threshold. The engine controller is configured toincrease the temperature of the diesel exhaust gas entering the dieselparticulate filter during the time region or distance region.

Another embodiment of the present invention provides a method forremoving particulate matter from a diesel particulate filter. The dieselparticulate filter includes at least one diesel particulate filter unitto filter the particulate matter from diesel engine exhaust gas receivedfrom a diesel engine of a locomotive. The method includes determiningthe extent of trapped particulate matter within the diesel particulatefilter unit by positioning at least one sensor adjacent to the at leastone of the diesel particulate filter unit. The method further includescreating a trip plan to optimize the performance of the locomotive alonga route in accordance with a power setting of the diesel engine at eachlocation along the route. The method further includes configuring eachsensor to output a first alert signal to the engine controller upon thetrapped particulate matter exceeding a predetermined threshold. Themethod further includes configuring the engine controller to communicatewith a locomotive controller upon receiving the first alert signal todetermine a time region or distance region within the trip plan when thepower setting of the diesel engine is greater than a power threshold.Additionally, the method includes configuring the engine controller toincrease the temperature of the diesel exhaust gas entering the dieselparticulate filter during the time region or distance region uponreceiving the first alert signal.

Another embodiment of the present invention provides a system forremoving particulate matter from a particulate filter. The particulatefilter includes at least one diesel particulate filter unit to filterthe particulate matter from the engine exhaust gas received from aninternal combustion engine of a locomotive. The system includes anengine controller coupled to the engine, where the engine controllerincludes a memory configured to store at least one loading rate of theat least one diesel particulate filter unit for at least one of adistance or time increment of the locomotive traveling along a route.The system further includes a locomotive controller coupled to theengine controller, where the locomotive controller includes an algorithmto create a trip plan to optimize the performance of the locomotivealong a route in accordance with a power setting of the engine at eachlocation along the route. The engine controller is configured tocommunicate with the locomotive controller upon the engine controllerhaving determined that a level of trapped particulate matter within theat least one diesel particulate filter exceeds a predeterminedthreshold. The engine controller is configured to calculate the level oftrapped particulate matter based upon an initial level of trappedparticulate matter and the at least one loading rate at a distance ortime increment. The engine controller is configured to further determinea time region or a distance region within the trip plan when the powersetting exceeds a power threshold. The engine controller is configuredto increase the temperature of the exhaust gas entering the particulatefilter during the time region or distance region.

Another embodiment of the present invention provides computer readablemedia containing program instructions for removing particulate matterfrom a diesel particulate filter. The diesel particulate filter includesat least one diesel particulate filter unit to filter the particulatematter from diesel engine exhaust gas received from a diesel engine. Thecomputer readable media includes a computer program code to configurethe engine controller to increase the temperature of the diesel exhaustgas entering the diesel particulate filter upon receiving the firstalert signal.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the invention briefly described abovewill be rendered by reference to specific embodiments thereof that areillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered to be limiting of its scope, the invention will bedescribed and explained with additional specificity and detail throughthe use of the accompanying drawings in which:

FIG. 1 depicts a schematic side view of an exemplary embodiment of asystem for reducing particulate matter emission in engine exhaust gas;

FIG. 2 depicts a schematic end view of an exemplary embodiment of asystem for reducing particulate matter emission in engine exhaust gas;

FIG. 3 depicts an isolated perspective view of an exemplary embodimentof a diesel engine among a system for removing particulate matter from adiesel particulate filter in accordance with the present invention;

FIG. 4 depicts a schematic side view of an exemplary embodiment of asystem for removing particulate matter from a diesel particulate filterin accordance with the present invention;

FIG. 5 depicts a schematic side view of an exemplary embodiment of asystem for removing particulate matter from a diesel particulate filterin accordance with the present invention;

FIG. 6 depicts an exemplary embodiment of a method for removingparticulate matter from a diesel particulate filter in accordance withthe present invention;

FIG. 7 depicts an exemplary embodiment of a method for removingparticulate matter from a diesel particulate filter in accordance withthe present invention; and

FIG. 8 depicts a schematic side view of an exemplary embodiment of asystem for removing particulate matter from a diesel particulate filterin accordance with the present invention.

FIGS. 9 and 10 illustrates tables listing example parameters ofSelective Catalyst Reduction (SCR) components as may be used in anexample aftertreatment system.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the embodiments consistent withthe invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numerals used throughoutthe drawings refer to the same or like parts.

FIGS. 1 and 2 illustrate exemplary embodiments of a wall-flow dieselparticulate filter 214 and a flow-through diesel particulate filter214′. The diesel particulate filter 214 illustrated in the exemplaryembodiment of FIGS. 1 and 2 is an example of an aftertreatment system,and similar examples may be constructed for wall-flow diesel particulatefilters, to chemically reduce any or all species in the diesel engineexhaust, such as hydrocarbons, CO, nitrous dioxide, and other chemicalsappreciated by one of skill in the art, as further discussed below inadditional embodiments of the present invention. As illustrated in FIG.1, a diesel particulate filter unit 216 (FIG. 3) includes a plurality ofchannels 226 aligned in a flow direction 230 of the diesel engineexhaust gas 212. The channels 226 of each diesel particulate filter unit216 are selectively configured with a distinct cross-sectional areadensity. The cross-sectional area density of a diesel particulate filterunit may be directly proportional to its resistance to a cross-sectionalregion of diesel exhaust gas. However, the cross-sectional area densityof the channels may be the same for different diesel particulate filterunits, or may be non-uniform across a diesel particulate filter unit.

As further illustrated in the exemplary embodiment of FIG. 1, aplurality of walls 232 are positioned to separate adjacent channels 226of the diesel particulate filter unit 216. The walls 232 of the dieselparticulate filter unit 216 are designed with a respective thickness.The wall thickness of the center diesel particulate filter unit 216 isgreater than the wall thickness of the outer diesel particulate filterunit 218. The respective wall thickness of a diesel particulate filterunit may be directly proportional to its resistance to a cross-sectionalregion of diesel exhaust gas. However, the wall thickness may be thesame for different diesel particulate filter units, or may benon-uniform across a diesel particulate filter unit.

As further illustrated in FIG. 1, a plurality of pores 240 arepositioned within the plurality of walls 232, and the pores 240 areconfigured to vacate a distinct ratio of the area of the walls 232. Thepores ratio of the walls of the center diesel particulate filter 216 islower than the pores ratio of the walls of the outer diesel particulatefilter 218. The pores ratio of the walls of a diesel particulate filtermay be inversely proportional to its resistance to a cross-sectionalregion of diesel exhaust gas. However, the pores ratio may be the samefor different diesel particulate filter units, or may be non-uniformacross a diesel particulate filter unit.

As further illustrated in FIGS. 1 and 2, the plurality of channels 226of the diesel particulate filter unit 216 include a plurality of firstchannels 256 with a blocked inlet 258 and an open outlet 260.Additionally, the plurality of channels 226 include a plurality ofsecond channels 262 with an open inlet 264 and a blocked outlet 266.Each first channel 256 is positioned adjacent to a second channel 262,and each second channel 262 is positioned adjacent to a first channel256. Although the first channel and second channel are illustrated inFIG. 1 with alternating blocked inlet/open inlet and blocked outlet/openoutlet, each diesel particulate filter unit may include one or morechannels with a blocked/open inlet and blocked/open outlet which is outof sequence with its adjacent channels.

During operation of the system 210, upon a respective cross-sectionalregion of the diesel exhaust gas 212 entering a second channel 262 of adiesel particular filter unit 216, the diesel exhaust gas is configuredto pass through one of the walls 232 separating the plurality of firstchannels 256 and plurality of second channels 262. The diesel exhaustgas 212 subsequently passes into a first channel 256 and exits throughthe open outlet 260 of the first channel 256 to the atmosphere. However,various other paths may be taken by the diesel exhaust gas 212 throughthe diesel particulate filter 216. Upon the diesel exhaust gas 212passing from the second channel 262, through the wall 232 and into thefirst channel 256, particulate matter of the diesel exhaust gas 212 istrapped within the pores 240 of the wall.

In designing each diesel particulate filter unit 216,218, the selectivecross-sectional area density of the plurality of channels, therespective wall thickness and the ratio of pores within the walls isselectively determined based upon a flow rate of the respectivecross-sectional region of the diesel exhaust gas 212 which is expectedto pass over the respective diesel particulate filter unit 216,218. Theplurality of diesel particulate filter units 216,218 may be comprised ofsilicon carbide, cordierite material, or any other material, orcombination of materials appreciated by one of skill in the art.

As illustrated in FIG. 3, the diesel particulate filter 214 may includea diesel particulate filter housing 248 for the plurality of dieselparticulate filter units 216,218. As further illustrated in FIG. 3, thediesel engine exhaust gas 212 is output from a locomotive diesel engine211 into a turbocharger 250 and subsequently from a turbocharger outletinto the diesel particulate filter 214. As further illustrated in FIG.3, the system 210 may include a catalyst device 268 positioned betweenthe turbocharger 250 and the diesel particulate filter 214, to receivethe diesel engine exhaust gas 212 output from the turbocharger. Thecatalyst device 268 is configured to increase the temperature of thediesel engine exhaust gas 212 directed into the diesel particulatefilter 214, and may be contained within the housing 248.

Although the embodiment of the system 210 to reduce particulate matteremission in diesel engine exhaust gas 212 involves the use of a dieselparticulate filter 214, various other aftertreatment systems may beutilized to control the distribution of exhaust flow over the crosssection of the flow path by using aftertreatment substrates withdifferent flow characteristics at the various locations across thechannel. The embodiments of the present invention all includeaftertreatment systems which may be used to alter the flowcharacteristic over the cross-section using a number of techniques. Asdescribed in the system 210 above, varying the cross-sectional areadensity and/or wall thickness of a wall-flow particulate filter (i.e., aparticulate filter with alternating blocked inlet-open outlet channels,and open inlet-blocked outlet channels) is one example of such anaftertreatment system. However, another exemplary embodiment of thepresent invention involves an aftertreatment system to combine awall-flow particulate filter 214, as illustrated in FIGS. 1 and 2, witha flow-through particulate filter 214′ (i.e., a diesel particulatefilter with an open inlet-open outlet channel arrangement), alsoillustrated in FIGS. 1 and 2 to get a favorable flow and thermalcharacteristic. Additionally, in an additional exemplary embodiment ofthe present invention, the materials of the flow-through particulatefilters 214′ or the wall-flow particulate filters 214 may be combined insuch a fashion to get such favorable flow and thermal characteristics,and such materials may include silicon carbide, cordierite, mullite, ormetal mesh, among others.

FIG. 4 illustrates another embodiment of a system 410″ for removingparticulate matter from a diesel particulate filter 414″. The dieselparticulate filter 414″ includes a plurality of diesel particulatefilter units to filter the particulate matter from diesel engine exhaustgas received from a diesel engine 411″ of a locomotive 441″. The system410″ includes a pair of sensors 420″, 422″ configured to determine theextent of trapped particulate matter within the diesel particulatefilter 414″. Additionally, the system 410″ includes an engine controller429″ coupled to the pair of sensors 420″, 422″ and the diesel engine411″. The system 410″ further includes a locomotive controller 444″coupled to the engine controller 429″, where the locomotive controller444″ includes an algorithm to create a trip plan to optimize theperformance of the locomotive 441″ along a route 434″ in accordance witha power setting of the diesel engine 411″ at each location along theroute 434″. Additional details of systems including such enginecontrollers are disclosed in U.S. application Ser. Nos. 11/622,136 and11/671,533, the entire contents of which are incorporated by referenceherein. In an exemplary embodiment of the present invention, theoptimization of the performance of the locomotive along the route 434″may be maximizing the fuel efficiency of the locomotive along the route,for example.

The system 410″ involves performing regeneration (ie. removing trappedparticulate matter) on the particulate filter 414″, or otheraftertreatment system, in cooperation with the algorithm of thelocomotive controller 444″. The system 410″ first determines the load,or extent, of trapped particulate matter within the particulate filter414″, using a variety of methods, such as a pair of sensors 420″, 422″described below. Alternatively, the system 410″ may estimate the load oftrapped particulate matter within the particulate filter 414″, usingexperimentally known load rates, and calculating an estimated load oftrapped particulate matter within the particulate filter 414″ atincremental time or distance regions along the locomotive trip. Once thesystem 410″ has estimated the load, or extent of trapped particulatematter within the particulate filter 414″, the system 410″ determines anupcoming distance or time limit gap until the particulate filter willbecome critically loaded with particulate matter, based upon theestimated particulate filter load, and future upcoming load rates. Thesystem 410″ determines a time or distance region within this respectivetime or distance limit gap to perform regeneration such that the enginenotch profile during this time or distance region is sufficient tooxidize the trapped particulate matter within the particulate filter. Asan example, the system may calculate that the particulate filter is 50%loaded with particulate matter, and estimate that it will become fullyloaded in the next 45 minutes. Thus, in this example, the system wouldanalyze the upcoming trip profile within the next 45 minutes anddetermine for ideal time to conduct a 20 minute regeneration cycle. Asdescribed in the previous example, the system 410″ may performregeneration prior to the particulate filter reaching a full loadcapacity. By performing the regeneration process during a time ordistance region of the locomotive trip when the upcoming engine notchprofile is sufficiently high, the engine exhaust temperature is alreadyelevated, and thus a minimal amount of energy needs to be added toincrease the engine exhaust temperature to oxidize the trappedparticulate matter.

The system 410″ provides further advantageous features, includingselectively choosing those distance or time regions among the respectivetime or distance limit gap to perform regeneration. For example,regeneration is not desired when the locomotive is traveling throughtunnels or within such closed areas, and thus the system 410″ mayselectively exclude distance or time regions from the trip profile whenperforming regeneration which overlap with the locomotive travelingthrough such closed regions or tunnels.

The pair of sensors 420″, 422″ are configured to continuously output afirst alert signal 432″ to the engine controller 429″, where each firstalert signal 432″ includes a current load and/or a loading rate ofparticulate matter within the diesel particulate filter 414″. Thus, thepair of sensors 420″, 422″ continuously determines a current load andloading rate of particulate matter within the diesel particulate filter414″, and transmit this current load and loading rate information, inthe form of a first alert signal 432″, to the engine controller 429″.Although FIG. 4 illustrates a pair of sensors 420″, 422″, only onesensor or more than two sensors may be utilized to determine the currentload and/or loading rate, such as based on sensing the back pressurefrom the diesel particulate filter, for example. The engine controller429″ continuously receives the first alert signal 432″ from the pair ofsensors 420″, 422″, including the current load and loading rate of thediesel particulate filter 414″, and the engine controller 429″communicates with the locomotive controller 444″ to determine aprojected load and/or a projected loading rate of particulate matterwithin the diesel particulate filter 414″ along the route 434″ basedupon the trip plan. Additionally, the engine controller 429″ isconfigured to communicate with the locomotive controller 444″ todetermine a time gap or a distance gap based on the trip plan along theroute 434″ until the particulate filter 414″ is fully loaded withparticulate matter. The engine controller 429″ subsequently determines atime region or distance region within the respective time gap ordistance gap to remove the particulate matter from the particulatefilter 414″, where determining the time region or distance region isbased on one or more of the current load, the loading rate, theprojected load during the time gap or distance gap, the projectedloading rate during the time gap or distance gap, and the time gap ordistance gap. Thus, for example, if the current load is 70% and theengine controller uses the known projected load and projected load ratesto determine a time gap of 45 minutes (ie. particulate filter will fillup within 45 minutes), the engine controller 429″ may determine a timeregion from t=20-25 minutes within the time gap, during which the tripplan (ie. engine output) is sufficiently high to completely oxidize theparticulate matter within the particulate filter 414″.

In an additional exemplary embodiment, the pair of sensors 420″, 422″are configured to output a first alert signal 432″ to the enginecontroller 429″ upon the trapped particulate matter within the dieselparticulate filter 414″ exceeding a predetermined threshold. Uponreceiving the first alert signal 432″, the engine controller 429″ isconfigured to communicate with the locomotive controller 444″ todetermine a time region or distance region within the trip plan when thepower setting of the diesel engine 411″ exceeds a power threshold. Forexample, if the power threshold is 500 HP, and from t=80-120 minutes ord=60-62 miles, the algorithm within the locomotive controller 444″determines that the power setting of the diesel engine 411″ will begreater than 500 HP, the time region of t=80-120 minutes or the distanceregion of d=60-62 miles is communicated from the locomotive controller444″ to the engine controller 429″. The engine controller 429″ is thenarranged to increase the temperature of the diesel exhaust gas enteringthe diesel particulate filter 414″ during the time region or distanceregion, in order to remove the trapped particulate matter within thediesel particulate filter, as discussed in the previous embodiments andin further detail below.

As further illustrated in the exemplary embodiment of FIG. 4, the system410″ further includes a locator element 430″ to determine a location ofthe locomotive 441″ along the route 434″. Such a locator element 430″may include any of a number of position determining devices, such as aGPS device, or wayside signals, for example. Additionally, the system410″ further includes a track characterization element 433″ to provideinformation about a track, including topographic information, asdiscussed further below. The locomotive controller 444″ isillustratively coupled to the locator element 430″ and the trackcharacterization element 433″, and may communicate with these componentsto determine present track topographic information and to project futuretrack topographic information for incremental positions along the route434″. The algorithm within the locomotive controller 444″ may utilizethe track information to estimate current and projected variousoperating characteristics of the locomotive 441″, such as power settingsof the diesel engine 411″ when the locomotive 441″ reaches each locationalong the route 434″, for example. The locomotive controller 444″ isoperable to receive information from the locator element 430″, the trackcharacterizing element 433″, and the engine controller 429″. Someexamples of such information provided by the track characterizationelement 433″ at each location along the route 434″ include a change inspeed restriction along the route, a change in a track grade along theroute, a change in track curvature along the route, and a change in atraffic pattern along the route, among others.

In the illustrated embodiment of the system 410″, the trackcharacterization element 433″ may further include an on-board trackdatabase 436″ configured to store an expected change in the track gradeat each location along the route, an expected change in the trackcurvature at each location along the route, a change in the trackpattern at each location along the route and/or an expected powersetting at each location along the route 434″. The track database 436″may include any information pertinent to the track topographicinformation and/or the power setting of the diesel engine 411″ at eachlocation along the route 434″. Additionally, the on-board track database436″ may store historic information for previous runs such as the powersetting at each location along a route 434″ or any such similarlocomotive operating condition at each location along the route 434″,for a particular locomotive 441″ along a particular route 434″, or forvarious locomotives along a particular route 434″. The engine controller429″ may communicate with the locomotive controller 444″ and receivesuch historic information for previous runs, including previous powersettings of the locomotive 441″ at each location along the route 434″,as communicated from the database 436″.

As further illustrated in FIG. 4, the system 410″ includes aturbocharger 450″ includes an exhaust manifold to receive the dieselengine exhaust gas from the diesel engine 411″ and an outlet to outputthe diesel exhaust gas to the diesel particulate filter 414″. The system410″ further includes an injector device 433″ positioned between theturbocharger 450″ and the diesel particulate filter 414″, where theinjector device 433″ is configured to selectively inject an adjustableamount of diesel fuel into the diesel engine exhaust gas exiting theoutlet. Additionally, the system 410″ includes a reactive device 438″positioned between the injector device 433″ and the diesel particulatefilter 414″. The reactive device 438″ is configured to selectivelyignite the adjustable amount of injected diesel fuel within the dieselengine exhaust gas upon entering an inlet of the reactive device 438″ toincrease the temperature of the diesel exhaust gas entering the dieselparticulate filter 414″. Various reactive devices may be used, such ascatalyst devices, fuel burners, and any other devices appreciated by oneof skill in the art. The injection timing of the reactive device 438″may be retarded with electronic fuel injection systems to increaseexhaust temperature. Additionally, with more advanced systems, such ascommon rail, a post injection may be used.

As further illustrated in the exemplary embodiment of FIG. 4, the system410″ includes a temperature sensor 442″ coupled to the engine controller429″ and positioned adjacent to the reactive device 438″. Thetemperature sensor 442″ is configured to determine the temperature ofthe diesel engine exhaust gas entering the reactive device 438″. Thetemperature sensor 442″ is further configured to transmit a second alertsignal 445″ to the engine controller 429″ upon measuring a temperaturelower than a first minimum threshold for the reactive device 438″ toignite the diesel fuel. The first minimum threshold depends on variousfactors, including the type of reactive device, including its materialcomponents, method of reacting with the fuel, ambient temperature, andother factors to determine the minimum temperature at which the reactivedevice will ignite the diesel fuel, thereby increasing the temperatureof the diesel exhaust gas containing the ignited diesel fuel. In anexemplary embodiment of the system 410″, the first minimum threshold isapproximately 200 degrees Celsius, and the temperature of the dieselengine exhaust gas is lower than the first minimum threshold when thelocomotive diesel engine is in an idle state. However, the first minimumthreshold may take any particular value consistent with a minimumtemperature at which the reactive device ignites injected diesel fuelwithin the diesel exhaust gas.

The engine controller 429″ is configured to increase the temperature ofthe diesel exhaust gas entering the reactive device 438″ to greater thanthe first minimum threshold upon the engine controller 429″ receivingthe first alert signal 432″ and the second alert signal 445″. Thus, theengine controller 429″ provides an initial increase in the temperatureof the diesel exhaust gas, to at least the first minimum threshold, toenable a subsequent increase in the temperature of the diesel exhaustgas via ignition of the injected diesel fuel by the reactive device438″.

To initially increase the temperature of the diesel exhaust gas, theengine controller 429″ is configured to provide this increase intemperature through a number of methods. For example, the enginecontroller 429″ is configured to communicate with the locomotivecontroller 444″ to determine the time region or distance region withinthe trip plan during which the engine controller 429″ is configured toincrease the temperature of the diesel exhaust gas entering the reactivedevice 438″ above the first minimum threshold. Thus, upon engaging incommunication with the locomotive controller 444″, the engine controller429″ receives a time region or distance region, such as t=80-120 minuteor d=60-62 miles when the diesel engine has a power setting greater thana power threshold, as discussed above, for example, and during which theengine controller 429″ causes an increase in the temperature of thediesel exhaust gas entering the reactive device 438″. Alternatively, theengine controller 429″ may be configured to electrically couple analternator 456″ of the diesel engine 411″ during the time region ordistance region to the turbocharger output to cause an increase in thetemperature of the diesel engine exhaust gas entering the reactivedevice 438″.

As discussed in the previous embodiments of the present invention andillustrated in FIG. 1, each diesel particulate filter unit 216,218 ofthe diesel particulate filter 414″ includes a plurality of channels 226oriented parallel with the flow direction 230 of the diesel engineexhaust. The pair of sensors 420″,422″ are a pair of pressure sensorspositioned on opposing sides of the plurality of channels 226 of theparticulate filter unit 216 (FIG. 1). The pressure sensors 420″,422″ areconfigured to transmit the first alert signal 432″ to the enginecontroller 429″ upon measuring a pressure difference across theplurality of channels 226 which exceed a predetermined pressurethreshold. As the trapped particulate matter accumulates within thewalls of the diesel particulate filter 414″, as discussed in theprevious embodiments, the pressure difference across a channel 226, asmeasured by the pressures sensors 420″, 422″, increases. Thepredetermined pressure threshold may be selectively determined basedupon a number of factors, including, for example, the time duration toremove the trapped particulate matter, the method of removing thetrapped particulate matter, and the temperature of removing the trappedparticulate matter.

After the engine controller 429″ increases the temperature of the dieselexhaust gas entering the reactive device 438″ above the first minimumthreshold, the temperature sensor 442″ measures this increase intemperature and transmits a third alert signal to the engine controller429″. Upon receiving the first alert signal 432″ and the third alertsignal during the time region or distance region, the engine controller429″ transmits an ignite signal to the reactive device 438″ to ignitethe injected fuel within the diesel engine exhaust to increase thetemperature of diesel engine exhaust passing through an outlet of thereactive device 438″ and into an inlet of the diesel particulate filter414″.

The reactive device 438″ may be a catalyst device 438″ and may includean internal catalyst component which facilitates igniting the injectedfuel of the diesel exhaust gas and increases the temperature of thediesel exhaust gas at a temperature lower than in an absence of thecatalyst device 438″. During the ignition of the injected fuel withinthe diesel exhaust gas, the temperature of the diesel exhaust gasentering the catalyst device 438″ increases to a first high temperaturethreshold to facilitate oxidization of the trapped particulate matterwithin the plurality of diesel particulate filter 414″. This oxidizationof the trapped particulate matter within the diesel particulate filter414″ at the first high temperature threshold is known as activeregeneration. The trapped particulate matter may include a carbonmaterial which oxidizes at the first high temperature threshold. In anexemplary embodiment of the present invention, the first hightemperature threshold may be approximately 550 degrees Celsius, theoxidization may occur within an approximate temperature range of 550-600degrees Celsius and the catalyst may be formed from cordierite, siliconcarbide, mullite, metallic material or any combination of appropriatematerials. However, other first high temperature threshold values andoxidization temperature ranges are possible, based on various factorsincluding the material used, the amount of particulate matter to beoxidized, and the time duration of the regeneration, for example. Thoseelements not discussed herein, are similar to those elements discussedin the previous embodiments, with four-hundred scale double-prime numberreference notation, and require no further discussion herein.

FIG. 5 illustrates an additional embodiment of a system 410′″ of thepresent invention. Unlike the embodiment of the system 410″ discussedabove and illustrated in FIG. 4, in which active regeneration is used tooxidize trapped particulate matter from the diesel particulate filter,the system 410′″ discloses a passive regeneration process to oxidizetrapped particulate matter form the diesel particulate filter.

The system 410′″ illustrated in FIG. 5 includes a turbocharger 450′″including an exhaust manifold to receive the diesel engine exhaust gasfrom the diesel engine 411′ and an outlet to output the diesel exhaustgas to the diesel particulate filter 414″. As discussed in the previousembodiment, the diesel particulate filter 414′″ includes a plurality ofdiesel particulate filter units including a plurality of channelsoriented parallel with the flow direction of the diesel engine exhaust.Additionally, a pair of pressures sensors 420′″,422′″ are positioned onopposing sides of the plurality of channels of the diesel particulatefilter 414′″. The pressure sensors 420′″,422′″ are configured totransmit the first alert signal 432′″ to the engine controller 429′″upon measuring a pressure difference across the channels which exceeds apredetermined pressure threshold, as discussed in the previousembodiments.

As further illustrated in the exemplary embodiment of FIG. 5, atemperature sensor 442′″ is coupled to the engine controller 429′″ andpositioned adjacent to the diesel particulate filter 414′″ including theplurality of diesel particulate filter units. The temperature sensor442′″ is configured to determine the temperature of the diesel engineexhaust gas entering the diesel particulate filter 414′″ including theplurality of particulate filter units. Additionally, the temperaturesensor 442′″ is further configured to transmit a second alert signal445′″ to the engine controller 429′″ upon measuring a temperature lowerthan a second maximum threshold for the diesel particulate filter 414′″.As discussed in further detail below, the second maximum threshold isthe minimum temperature of the diesel exhaust gas at which the trappedparticulate matter within the diesel particulate filter 414′″ willoxidize in the presence of nitrous dioxide. The engine controller 429′″is configured to increase the temperature of the diesel exhaust gasduring the time region or distance region entering the dieselparticulate filter 414′″ to the second maximum threshold upon the enginecontroller 429′″ receiving the first alert signal 432′″ and the secondalert signal 445′″ to facilitate oxidization of the particulate matteron the plurality of particulate filter units in the presence of nitrousdioxide.

To increase the temperature of the diesel exhaust gas entering thediesel particulate filter 414′″, the engine controller 429′″ isconfigured to increase the temperature of the diesel engine exhaust gasduring the time region or distance region through facilitating thepassage of diesel engine exhaust gas into the particulate filter 414′″.The diesel engine 411′″ is configured with a power setting greater thanthe power threshold during the time region or distance region, asdiscussed previously. Alternatively, the engine controller 429′″ isconfigured to electrically couple an alternator 456′″ of the dieselengine 411′″ during the time region or distance region to theturbocharger output to cause an increase in the temperature of thediesel engine exhaust gas entering the plurality of diesel particulatefilter units of the diesel particulate filter 414′″. Although FIG. 5illustrates the above-described arrangements to increase the temperatureof the diesel exhaust gas, various other arrangements and methods may beutilized to increase the temperature of the diesel exhaust gas enteringthe diesel particulate filter. In an exemplary embodiment of the presentinvention, the second maximum threshold may be approximately 250 degreesCelsius and the oxidization in the presence of nitrous dioxide may occurin the approximate temperature range of 250-350 degrees Celsius.However, other second maximum threshold values and oxidizationtemperature ranges are possible, based on various factors including thematerial used, the amount of particulate matter to be oxidized, and thetime duration of the regeneration, for example. Additionally, in theillustrated embodiment of FIG. 5, a nitrous dioxide filter 466′″ ispositioned upstream from the particulate filter 414′″ to reduce thepresence/concentration of nitrous dioxide in the diesel exhaust gaswhich enters the diesel particulate filter.

FIG. 6 illustrates an exemplary embodiment of a method 600 for removingparticulate matter from a diesel particulate filter 414′″. Theparticulate filter 414′″ includes at least one particulate filter unitto filter the particulate matter from the engine exhaust gas receivedfrom an engine 411′″ of a locomotive 441′″. The method 600 begins (block601) by transmitting (block 602) a first alert signal 432′″ including atleast one of a current load and a loading rate of particulate matterwithin one or more particulate filter units from at least one sensor420′″,422′″ adjacent to an engine controller 429′″. The method 600further includes creating (block 604) a trip plan to optimize theperformance of the locomotive along a route 434′″ in accordance with apower setting of the engine 411′″ at each location along the route434′″. The method 600 further includes determining (block 606) aprojected load and projected loading rate of one or more particulatefilter units along the route 434′″ based upon the trip plan. The method600 further includes determining (block 608) a time gap or distance gapbased upon the trip plan along the route 434′″ until the one or moreparticulate filter unit is fully loaded with particulate matter. Themethod 600 further includes determining (block 610) a time region ordistance region within the respective time gap or distance gap to removethe particulate matter from the one or more particulate filter units.The step of determining the time region or distance region is based uponat least one of the current load, the loading rate, the projected load,the projected loading rate, the time region and the distance region. Themethod 600 further includes increasing (block 612) the temperature ofthe exhaust gas entering the particulate filter 414′″ during the timeregion or distance region, before ending at block 613.

FIG. 7 illustrates an exemplary embodiment of a method 700 for removingparticulate matter from a diesel particulate filter 414′″. The dieselparticulate filter 414′″ includes at least one diesel particulate filterunits to filter the particulate matter from diesel engine exhaust gasreceived from a diesel engine 411′″ of a locomotive 441′″. The method700 begins at 701 by determining (block 702) the extent of trappedparticulate matter within the diesel particulate filter 414′″ bypositioning a pair of sensors 420′″, 422′″ adjacent to the dieselparticulate filter 414′″. The method 700 further includes creating(block 704) a trip plan to optimize the performance of the locomotive441′″ along a route 434′″ in accordance with a power setting of thediesel engine 411′″ at each location along the route. The method 700further includes configuring (block 706) the pair of sensors 420′″,422′″ to output a first alert signal 432′″ to the engine controller429′″ upon the trapped particulate matter exceeding a predeterminedthreshold. The method 700 further includes configuring (block 708) theengine controller 429′″ to communicate with a locomotive controller444′″ upon receiving the first alert signal 432′″ to determine a timeregion or distance region within the trip plan when the power setting ofthe diesel engine 411′″ is greater than a power threshold. Additionally,the method 700 includes configuring (block 710) the engine controller429′″ to increase the temperature of the diesel exhaust gas entering thediesel particulate filter 414′″ during the time region or distanceregion upon receiving the first alert signal 432′″.

Another embodiment of the present invention is illustrated in FIG. 8 andprovides a system 410″″ for removing particulate matter from aparticulate filter 414″″. Unlike the systems illustrated in FIG. 4, thesystem 410″″ does not provide sensors to determine the extent of trappedparticulate matter within the particulate filter, and instead the enginecontroller 429″″ includes an internal memory 448″″ into which is storeda plurality of load rates of the particulate filter, at each time ordistance region along the locomotive route. The load rates at each timeor distance region may be determined experimentally, or may be basedupon previous data from the same locomotive along the same route or asimilar locomotive along the same route. The engine controller isconfigured to calculate the level of trapped particulate matter withinthe particulate filter 414″″ based upon an initial level of trappedparticulate matter and a plurality of loading rates during a respectiveplurality of time or distance increments along the locomotive route434″″. As described above, the engine controller 444″″ is configured toperform an initial calculation of a time or distance limit gap until theparticulate filter is fully loaded with trapped particles, and then isconfigured to subsequently determine a time or distance region withinthe time or distance limit gap when the power setting exceeds a powerthreshold. The engine controller is configured to increase thetemperature of the exhaust gas entering the particulate filter duringthe time region or distance region such that the trapped particleswithin the particulate filter are oxidized. Those elements of the system410″″ not discussed, are similar to those elements of the aboveembodiments, with quadruple prime notation, and require no furtherdiscussion herein.

While the invention has been described in what is presently consideredto be a preferred embodiment, many variations and modifications willbecome apparent to those skilled in the art. Accordingly, it is intendedthat the invention not be limited to the specific illustrativeembodiment but be interpreted within the full spirit and scope of theappended claims.

That which is claimed:
 1. A method for removing particulate matter froma particulate filter used to filter engine exhaust gas from an engine ofa vehicle, said method comprising: creating a trip plan to control thevehicle along a route, the trip plan specifying power settings of saidengine at corresponding locations along the route; determining an extentof trapped particulate matter within said particulate filter; upon saidextent of trapped particulate matter exceeding a predetermined thresholdduring a mission performed pursuant to said trip plan, analyzingupcoming portions of said trip plan to identify a time region ordistance region during which to perform a regeneration cycle of saidparticulate filter based upon at least an upcoming power setting beinggreater than a power threshold, said upcoming power setting specified bysaid trip plan for said time region or distance region identified; andperforming said regeneration cycle during said time region or distanceregion.
 2. The method of claim 1, wherein said upcoming portions of saidtrip plan occur after a portion of a mission during which said at leastone sensor output said first alert signal to said engine controller uponsaid trapped particulate matter exceeding a predetermined threshold andbefore a projected portion of said mission during which said particulatefilter is projected to be fully loaded.
 3. The method of claim 1,wherein said performing said regeneration cycle comprises: selectivelyinjecting an amount of fuel during said time region or distance regioninto engine exhaust gas exiting an output of a turbocharger of theengine; and selectively igniting said amount of injected fuel with areactive device.
 4. The method of claim 3 further comprising:determining a temperature of said engine exhaust gas adjacent to saidreactive device; and upon measuring a temperature lower than a firstminimum threshold for said reactive device to ignite said injected fuel,increasing said temperature of said exhaust gas adjacent said reactivedevice above said first minimum threshold.
 5. A method comprising:transmitting, to an engine controller of an engine of a vehicle, a firstalert signal comprising at least one of a current load and a loadingrate of particulate matter within at least one particulate filter unitfrom at least one sensor adjacent to said at least one particulatefilter unit, said at least one particulate filter unit configured tofilter said particulate matter from engine exhaust gas received fromsaid engine; creating a trip plan to control the vehicle along a route;determining a projected load and projected loading rate of said at leastone particulate filter unit along said route based upon said trip plan;determining a time gap or distance gap based upon said trip plan alongsaid route until said at least one particulate filter is fully loadedwith said particulate matter; determining a time region or distanceregion within said respective time gap or distance gap to remove saidparticulate matter from said at least one particulate filter unit, saiddetermining said time region or distance region based upon at least oneof said current load, said loading rate, said projected load, saidprojected loading rate, said time region and said distance region; andincreasing a temperature of said exhaust gas entering said at least oneparticulate filter unit during said time region or distance region.
 6. Asystem comprising: at least one sensor configured to determine theextent of trapped particulate matter within at least one particulatefilter unit of a particulate filter, said particulate filter unitconfigured to filter said particulate matter from engine exhaust gasreceived from an internal combustion engine of a vehicle; an enginecontroller coupled to said at least one sensor and said engine; and avehicle controller coupled to said engine controller, said vehiclecontroller configured to create a trip plan to control said vehiclealong a route, the trip plan specifying power settings of said engine atcorresponding locations along the route; wherein said at least onesensor is configured to output a first alert signal to said enginecontroller upon said trapped particulate matter exceeding apredetermined threshold, said engine controller is configured tocommunicate with said vehicle controller upon receiving said first alertsignal to analyze upcoming portions of said trip plan to identify a timeregion or distance region during which to perform a regeneration cycleof said particulate filter unit based upon at least an upcoming powersetting being greater than a power threshold, said upcoming powersetting specified by said trip plan for said time region or distanceregion identified, and said engine controller is configured to increasethe temperature of said exhaust gas entering said at least oneparticulate filter unit during said time region or distance region. 7.The system of claim 6, wherein said vehicle comprises a locomotive. 8.The system of claim 6, wherein said upcoming portions of said trip planoccur after a portion of a mission during which said at least one sensoroutput said first alert signal to said engine controller upon saidtrapped particulate matter exceeding a predetermined threshold andbefore a projected portion of said mission during which said particulatefilter unit is projected to be fully loaded.
 9. A system comprising: atleast one sensor configured to determine at least one of a current loadand a loading rate of particulate matter within at least one particulatefilter unit, said at least one particulate filter unit configured tofilter said particulate matter from engine exhaust gas received from aninternal combustion engine of a vehicle; an engine controller coupled tosaid at least one sensor and said engine; and a vehicle controllercoupled to said engine controller, said vehicle controller configured tocreate a trip plan to control the vehicle along a route; wherein said atleast one sensor is configured to continuously output a first alertsignal to said engine controller, said first alert signal including saidcurrent load and said loading rate of said at least one particulatefilter unit, said engine controller is configured to determine aprojected load and projected loading rate of said at least oneparticulate filter unit along said route based upon said trip plan, saidengine controller is configured to communicate with said vehiclecontroller to determine a time gap or distance gap based upon said tripplan along said route until said at least one particulate filter unit isfully loaded with said particulate matter, said engine controller isconfigured to determine a time region or distance region within saidrespective time gap or distance gap to remove said particulate matterfrom said at least one particulate filter unit, said determination ofsaid time region or distance region based upon at least one of saidcurrent load, said loading rate, said projected load, said projectedloading rate, and said time gap or said distance gap, said enginecontroller being configured to increase a temperature of said exhaustgas entering said at least one particulate filter unit during said timeregion or distance region.
 10. A method comprising: determining anextent of trapped particulate matter within said at least oneparticulate filter unit using at least one sensor positioned adjacent tosaid at least one particulate filter unit, said at least one particulatefilter unit configured to filter said particulate matter from engineexhaust gas received from an engine of a vehicle; creating a trip planto control the vehicle along a route in accordance with a power settingof said engine at each location along the route; outputting a firstalert signal to an engine controller upon said trapped particulatematter exceeding a predetermined threshold; communicating with a vehiclecontroller upon said engine controller receiving said first alert signalto determine a time region or distance region within said trip plan whensaid power setting of said engine is greater than a power threshold;receiving said engine exhaust gas in a turbocharger; selectivelyinjecting an amount of fuel during said time region or distance regionwith an injector device into said engine exhaust gas exiting an outputof said turbocharger; selectively igniting said amount of injected fuelduring said time region or distance region within a reactive device,said injected fuel within said engine exhaust gas entering an inlet ofsaid reactive device; determining the temperature of said engine exhaustgas adjacent to said reactive device; transmitting a second alert signalto said engine controller upon measuring a temperature lower than afirst minimum threshold for said reactive device to ignite said injectedfuel; and communicating with said vehicle controller upon said enginecontroller receiving said first and second alert signals, to determinesaid time region or distance region within said trip plan during whichsaid engine controller is configured to increase the temperature of saidexhaust gas entering said reactive device above said first minimumthreshold.